Hydrangea macrophylla f. normalis ("Gakuajisai")

Japanese name: ガクアジサイ
Scientific name: Hydrangea macrophylla f. normalis

[Overview]
A deciduous to semi-evergreen shrub 2–3 m tall, found in seaside woods, forest edges, and Japanese pampas grass (susuki) meadows.
It branches freely from the base.
The leaves are simple and opposite, 10–15 cm long and 5–10 cm wide, oblong to ovate-elliptic, with triangular teeth on the margin.
The upper surface of the leaves is glossy.
The petiole is 1–4 cm long.
A cyme-like inflorescence 10–20 cm across is produced at the branch tips.
The inflorescence has purplish-tinged white, 4-petaled ornamental flowers 3–4 cm across around the edge, and many pale blue or pale bluish-purple bisexual flowers in the center.
The bisexual flowers have 5 petals that fall easily, and 10 stamens of the same color as the petals.
Flower color is affected by soil acidity.
The fruit is an elliptic to ovate capsule 6–9 mm long.

[Cultivation]
Propagate by cuttings.
It prefers sun to partial shade and moist, fertile soil with good drainage and good water retention.
It prefers slightly acidic soil; the original flower color is blue, but in alkaline soil it becomes reddish.
It tolerates shade, but flowers poorly.
It is unsuitable for places where the soil becomes extremely dry or where strong afternoon sun falls.
It absorbs a lot of water, so for potted plants take care that they do not dry out, and water thoroughly when the soil surface dries.
Watering is not particularly necessary for plants in the ground, but in the high temperatures of summer water in the morning or evening when the temperature is lower.
Apply slow-release fertilizer twice a year, in winter and as a thank-you fertilizer after flowering.
Pests and diseases include powdery mildew, anthracnose, scale insects and aphids.

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